In device-to-device communications, user equipments (UEs) communicate with each other. Conventional UEs are equipped to transmit on the uplink and receive on the downlink, while base stations receive on the uplink and transmit on the downlink. Device-to-device communication may be used for at least public safety and social networking.
To improve public safety, device-to-device communication is used where the cellular infrastructure is unavailable. Device-to-device communication allows user equipments (UEs) to communicate with each other directly in emergency situations.
Device-to-device communication is also used in social networking for commercial applications. More specifically, device-to-device communication allows proximate UEs to share information.